Screw driver having expanding screw holding bit



June 9- E. 1.. MILLEN 2,472,673

SCREW DRIVER Hume nxmimma SCREW HOLDING BIT Filed Oct; 11, 1945 INVENTOR.

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w 7f w Patented June 7, 1949 tlNlTED STA'iEfi FATENT OFFICE SCREW DRIVERHAVING EXPANDING SCREW HGLDING BIT 1 Claim. 1

The present invention relates to a. screw driver particularly to thetype for holding the screw by means of a gripping device provided in theoi the blade of the screw driver.

Que of the difficulties encountered with screw drivers of this type isthat a blade so formed usually weakened because the blade end is not anintegral piece and easily becomes bent out of alignment so that it doesnot operate properly particularly when spring pressure alone is reliedupon for moving the blade or the tongue in the blade back to its normalposition.

In the present application the tongue which produces the gripping actionin the screw slot is centrally located in a recess in the blade, therecess bein formed only on one face of the blade and not separating theblade into forked ends. Further, the tongue is positively moved from aposition in the recess to a position out of the recess by the sliding ofa collar on the shank of 1e screw driver.

A further advantage in the present invention is to be found in theaction of the collar which is provided with considerable motionlongitudinally of the screw driver shank so that a tight adjustment ofthe end of the blade in the screw slot may readily be obtained. Thecollar automatically locks the tongue in place so that the screw will befirmly retained in the end of the blade until it is properly inserted inits place.

The invention will be more fully described in connection with theembodiment described in the specification annexed hereto when taken inconnection with the drawings illustrating the same in which:

Figure 1 shows a longitudinal view of the shank and blade end of thescrew driver to which the present invention is applied.

Figure 2 shows a View as seen from the top of the screw driver in theposition shown in Figure 1.

Figure 3 shows a section taken on the line 3-3 of Figure 2.

Figure 4 shows a section taken on the line it-4 of Figure 1.

Figure 5 is an end view as seen end of Figure 2.

In the arrangement of the figures described, 1 represents the shank ofthe screw driver and 2 the blade, the handle not being shown in thedrawings. It will be noted that the shank and blade are slotted by acontinous slot 3 which is deeper in the central portion of its lengththan at its ends and forms a well or recess for receiving the adjustableor pivoted tongue element 4.

from the right The recess 3, it will be noted, is centrally andsymmetrically positioned with respect to the longitudinal axis of thescrew driver throughout the shank and blade. At the end of the blade 5the slot 3 becomes a shallow channel, as indicated by B in Figure 5, inwhich the rectangular end 'i of the tongue rests. The tongue l ispivoted to the blade 2 by means of a ring 8 which fits closely aroundthe cylindrical blade 2 and passes through a hole in the blade, the holebeing tangent to the surface of the blade or slightly below the surfacein which case the blade may be slightly grooved to make a snug fit forthe ring 6. As indicated, the upper sectional portion of the ringelement in Figure 3 is shown tangential to the dotted line 9 indicatingthe position of the surface of the blade at that point. The tongue l isformed with a comparatively fiat edge it which for the most part issubstantially parallel with the base of the channel 3 at its bottom edgeand arched by a long arch H at its top edge which gradually tapers withtwo shoulders i2 and i3 intervening before the straight portion M whichterminates in a curved, hooked end iii. The collar [6 surrounds theshank l and has a free sliding fit over the shank with normal allowancefor longitudinal motion with respect to the blade. The collar It has anarched outer surface I8 adapted to fit into the curved end or hock l5 atthe end of the tongue when the collar is in a position as indicated inthe drawings and an outwardly extending flange H which may serve as agrip for moving the collar. The collar may be moved from this positionto the right, as viewed in Figures 1, 2 and 3, in which case it passesover the shoulder l3 and moves over the tapered surface [9 toward theshoulder E2. The movement of the collar over the shoulder i3 and thetapered surface l2 gradually raises the end i of the tongue out of therecess 6 exerting pressure against the wall of the screw slot when theend of the blade is inserted therein. The inclination of the surface i9is such that the collar it will remain in the position it is put untilchanged manually. Therefore, the screw will remain held until it is inplace and released only by drawing backward the collar I6. A shoulder 12is provided in the blade 4 to limit the motion of the collar on theblade in one direction while the curved or hooked end l5 limits themotion of the collar in the other direction. The limiting motionindicated in Figure 3 is sufficient to place the blade end completely inthe recess, making a smooth ended screw driverwhich may be used in theusual manner. In fact, it is customary after the screw has once beeninserted to pull back the collar I6 to its furthest position therebyreplacing the tongue before screwing the screw down in place.

Having now described my invention, I claim:

A screw driver havin a blade, the free end of which is adapted to bemounted in a screw slot, said blade havinga recess formed longitudinallyin it, a tonguepos'itioned therein, means pivotally mounting said tongueon an axis perpendicular to the recess, the bottom of said recess beingspaced from the bottom of the tongue, whereby the tongue may be movedabout the pivot point,- said tongue having a shape at the free endof theblade to form with the blade a continuous surface when the tongue is inan inward position, said tongue at the other and terminating in a hookedsection with the end portion bent over the tongue and spaced from thesurface of the blade and a section adjacent the hooked section flushwith the surface of the bladeand a further section adjacent thelastmentioned section having a shoulder rising above the surface of the4 blade, a collar normally positioned on the blade in said flushsection, said collar having a cam shape whereby when moved under the topportion of said hook, it will engage within the hook and raise it,thereby depressing the other end of the tongue into said inwardposition, and when said collar is moved in the other direction it willride on said shoulder, depressing the same to raise the other end of thetongue out of the recess.

EDWARD L. MILLEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

